Is dilution with normal saline required for administration of alteplase (tissue plasminogen activator) in acute myocardial infarction?

Dilution with Normal Saline for Alteplase in Acute Myocardial Infarction

No dilution with normal saline is required for alteplase administration in acute myocardial infarction—the drug is administered directly as reconstituted per manufacturer instructions. 1

Standard Administration Protocol for MI

The European Society of Cardiology guidelines specify the exact dosing regimens for alteplase in STEMI, and none require normal saline dilution 1:

• Alteplase is given as: 15 mg IV bolus, followed by 0.75 mg/kg over 30 minutes (up to 50 mg), then 0.5 mg/kg over 60 minutes (up to 35 mg) 1
• The medication is administered directly after reconstitution without additional dilution 1

Critical Distinction: MI vs. Stroke Dosing

A major pitfall is confusing MI and stroke protocols—these are completely different regimens and must never be interchanged. 1, 2, 3

For Myocardial Infarction:

• Total dose varies by weight with different infusion rates 1
• Front-loaded regimen: 15 mg bolus + 50 mg over 30 min + 35 mg over 60 min 1
• No saline dilution specified in guidelines 1

For Stroke (DO NOT use for MI):

• 0.9 mg/kg (maximum 90 mg total) 1
• 10% as bolus over 1 minute, 90% infusion over 60 minutes 1
• This stroke protocol is explicitly contraindicated for MI use 1, 2

Practical Administration Considerations

The key is following the reconstitution instructions from the manufacturer without additional dilution steps: 1

• Reconstitute alteplase vials according to package insert 1
• Draw up calculated dose directly into syringe for bolus 1
• Use infusion pump for continuous portions without further dilution 1

Adjunctive Therapy Requirements

When administering alteplase for MI, concurrent medications are mandatory 1:

• Aspirin: 150-300 mg orally or 80-150 mg IV must be given 1
• Clopidogrel: Loading dose of 600 mg orally 1
• Anticoagulation: Enoxaparin IV followed by subcutaneous (preferred over unfractionated heparin) or weight-adjusted UFH bolus and infusion 1

Common Errors to Avoid

Never attempt to use stroke dosing protocols for myocardial infarction—this represents a critical medication error with potential for harm. 1, 2, 3

• The 0.9 mg/kg stroke dose is insufficient for MI 1, 2
• The MI front-loaded regimen would cause excessive bleeding risk in stroke 1, 2
• Always verify you are using the correct indication-specific protocol 1, 2, 3